Pecorino sardo, also known as fiore sardo, is a firm cheese from the Italian island of Sardinia which is made from sheep milk: specifically from the milk of the local Sardinian breed. It was awarded Denominazione d'Origine status in 1991 and granted Protected designation of origin (PDO) protection in 1996, the year in which this European Union certification scheme was introduced. Its flavour is different from that of the Pecorino Romano, which is also made in the island. Sardo is richer while romano is much more biting and salty. Pecorino sardo is delicious in contexts where the romano could overpower, such as in pesto—the Ligurian pesto alla genovese is tradionally made with a mixture of Pecorino sardo and Parmigiano-Reggiano—or with fruit.
Pecorino sardo is an uncooked hard cheese made from fresh whole sheep's milk curdled using lamb or kid rennet. The mixture is poured into moulds that will give the cheese its characteristic shape. After a brief period in brine, the moulds are lightly smoked and left to ripen in cool cellars in central Sardinia. The average weight of the finished product is 3.5 kilos: sometimes a bit more, sometimes a bit less depending on the conditions of manufacture. The rind varies from deep yellow to dark brown in colour and encases a paste that varies from white to straw-yellow. The sharpness of the flavour depends on the length of maturation. It's most often found in the United States as a hard cheese, its more mature form.
Pecorino sardo is not as well known outside Italy as romano or Pecorino Toscano, although a good deal of Pecorino Romano is actually made in Sardinia, as Sardinia is within Romano's PDO area. Pecorino sardo can be processed further into Casu marzu (Sardinia's signature dish) by the introduction of cheese fly maggots.